赤泥基生物炭载体对厌氧氨氧化污泥富集的影响研究

Effect of red mud-based biochar carrier on the enrichment of anaerobic ammonia oxidation sludge

为了实现厌氧氨氧化(Anammox)污泥的快速富集,以赤泥为铁源、以斑茅秸秆为生物炭前驱体制备赤泥基生物炭载体,并将其与处理养殖沼液的自然塘污泥混合均匀后,投加至上流式厌氧污泥床(UASB)反应器中,考察了Anammox污泥驯化过程中反应器的脱氮性能、污泥性能、微生物群落结构的变化情况,评估了赤泥基生物炭载体对Anammox污泥富集的影响机理.结果表明:历经59d,添加了赤泥基生物炭载体的R2反应器可成功富集Anammox污泥,其NH_(4)^(+)-N和NO_(2)--N去除速率分别为1.47kg/(m^(3)·d)和1.91kg/(m^(3)·d),而未投加的R1反应器至92d时才成功富集Anammox污泥;污泥驯化过程中,R2污泥的胞外聚合物(EPS)分泌量明显高于R1,且R2污泥颗粒粒径大小和颗粒化程度明显大于R1;至驯化末期,观察到R2中有大量的厌氧氨氧化菌(AnAOB)附着在赤泥基生物炭载体的孔道内,且孔道内的AnAOB周边存在大量的铁元素,而R1的AnAOB则相对较少且分散,R2污泥比厌氧氨氧化活性(SAA)是R1的2.3倍,Anammox基因拷贝数是R1的3.8倍.由此可见,赤泥基生物炭载体可明显加快Anammox污泥的富集,其不仅为AnAOB提供了“房子”以抵御不利环境,“房子”内的赤泥活性组分如铁等可能在AnAOB的代谢和团聚生长方面具有促进作用,且赤泥基生物炭载体采用固体废弃物制成,在实际应用中具有经济有效性.

To achieve rapid enrichment of anaerobic ammonia oxidation(Anammox)sludge,the red mud-based biochar carrier was prepared using red mud as the iron source and Erianthus arundinaceus straw as the biochar precursor,and then mixed it with the natural pond sludge treated for aquaculture digestate and dosed into an up-flow anaerobic sludge bed(UASB)reactor.The changes in the nitrogen removal performance,sludge performance and microbial community structure of reactors during the domestication of Anammox sludge were investigated,and the effect mechanism of the red mud-based biochar carriers on Anammox sludge enrichment was evaluated.We found that the Anammox sludge was successfully enriched in R2reactor containing red mud-based biochar carrier after 59days incubation,and the removal rates of NH_(4)^(+)-N and NO_(2)^(-)-N were 1.47kg/(m^(3)·d)and 1.91kg/(m^(3)·d),respectively.Whereas the Anammox sludge enrichment was happened in R1reactor without carrier at day 92.Compared with R1 reactor,R2 reactor showed significantly effective in the process of Anammox sludge domestication,including the extracellular polymeric substances(EPS)secretion,sludge particle size and granulation.At the end of domestication,high population of anaerobic ammonia oxidizing bacteria(AnAOB)attached to the pores of red mud-based biochar carrier and accumulated iron surrounding AnAOB were observed in R2reactor,while the AnAOB from R1reactor were relatively small and dispersed.The specific anaerobic ammonia oxidation activity(SAA)of R2 was 2.3 times higher than that of R1,and the Anammox gene copy number from R2 was increased by 3.8times comparison from R1 at the end of domestication.These results suggest that the red mud-based biochar carrier could markedly accelerate the enrichment of Anammox sludge.This carrier not only provides a"house"for AnAOB to resist the unfavorable environment,also plays a role in the metabolism and agglomeration growth of AnAOB which depends on the active components of red mud,iron.Importantly,the red mud-based biochar carrier was made of solid waste,which is economically effective in practical applications.